1. Field of the Invention
Exemplary embodiments of the present invention provide a method for driving a light source and a light source apparatus for performing the method. More particularly, exemplary embodiments of the present invention provide a two-way dimming method for driving a light source and a light source apparatus for performing the method used in a liquid crystal display (“LCD”) apparatus.
2. Description of the Related Art
Generally, a liquid crystal display (“LCD”) apparatus displays an image by controlling electrical and optical characteristics of liquid crystal. LCD apparatuses have various advantages over other types of display apparatuses, such as smaller thickness, lighter weight, lower power consumption and lower driving voltage, for example. Accordingly, the LCD apparatuses are widely used in monitors, laptop computers, cellular phones and televisions, for example. The LCD apparatus typically includes an LCD panel which displays the image by controlling a light transmittance of the liquid crystal and a backlight assembly disposed under the LCD panel to provide light to the LCD panel.
The LCD panel typically includes an array substrate having thin-film transistors (“TFTs”) disposed in a substantially matrix pattern thereon, a color filter substrate disposed opposite to, e.g., facing, the array substrate and a liquid crystal layer interposed between the array substrate and the color filter substrate.
The backlight assembly includes a light source which generates the light for displaying the image on the LCD panel. The light source may be, for example, a cold cathode fluorescent lamp (“CCFL”), a hot cathode fluorescent lamp (“HCFL”) or a light-emitting diode (“LED”). In addition, a plurality of LEDs has also been used as the light source, since LEDs have low power consumption and high color reproducibility, as compared to other types of light sources.
The LCD apparatus typically further includes a driving part and a controlling part for driving the backlight assembly. More specifically, the controlling part controls the driving part using a pulse width modulation (“PWM”) control method, for example, for controlling a light intensity of LEDs of the plurality of LEDs based on characteristics of high-speed driving the LEDs. The PWM control method provides the LEDs with a static current by generating pulses, comparing pulse widths and modulating pulse widths, for example.
The plurality of LEDs typically includes a red LED, a green LED and a blue LED (“RGB LEDs”). Red light, green light and blue light, emitted from the red LED, the green LED and the blue LED, respectively, are mixed to emit white light and/or light of different colors.
When the RGB LEDs are disposed in packages, however, manufacturing costs are higher than manufacturing costs for a backlight assembly including white LEDs. In addition, when the RGB LEDs are disposed in a single package, a required number of wires connected to the single package is substantially increased.
Therefore, a two-way dimming method using two LEDs to generate both a standard RGB (“sRGB”) color space and an ADOBE® RGB color space is required.